bar graph
a graph in which a free-standing vertical bar is centered over each score on the X axis; used with nominal or ordinal scores
bimodal distribution
a symmetrical frequency polygon with two distinct humps where there are relatively high-frequency scores and with center scores that have the same frequency
deviation
the distance that separates a score from the mean and thus indicates how much the score differs from the mean
line graph
a graph of an experiment when the independent variable is an interval or ratio variable; plotted by connecting the data points with straight lines
mean
the score located at the mathematical center of a distribution
measure of central tendency
a score that summarizes the location of a distribution on a variable by indicating where the center of the distribution tends to be located
median
the score located at the 50th percentile; symbolized by Mdn
mode
the most frequently occurring score in a sample
sum of X
the sum of the scores in a sample
sum of the deviations around the mean
the sum of all differences between the scores and the mean
unimodal distribution
a distribution whose frequency polygon has only one hump and thus has only one score qualifying as the mode
